(1) Field of the Invention
The present invention relates to an apparatus for testing the stability of heavy oil. More particularly, the present invention relates to an apparatus suitable for testing the stability of heavy oil not only in a well-equipped laboratory but also in other places, for example, on a vessel.
(2) Description of the Prior Art
In the field of marine business and the like, the problem of the quality of fuels has attracted worldwide attentions, and various efforts have been made to cope with troubles owing to fuel oils and improve the quality of fuels.
What is most important among properties of marine heavy oil is the stability having a close relation to formation of sludge in heavy oil, and also the method of evaluation of this stability is important.
We made researches with a view to developing a simple method of testing the stability of heavy oil having a good conformity with occurrence of a trouble in a centrifugal cleaner, strainer or storing tank in the field and being adoptable for ordinary quality control. As the result, we found that a novel spot test method based on the ASTM spot test (ASTM D-2781-82) and improved to expand the application range has a good conformity with the actual working state and the stability can be simply evaluated according to this method.
This novel spot test method is introduced on pages 22 and 23 of Nisseki Technical Review, Volume 25, No. 5 (published in December 1983 by Nippon Oil Co., Ltd.).
The operation procedures of this spot test method are summarized below.
(1) A heavy oil sample is maintained at a temperature of 90.degree. to 100.degree. C. for 15 to 20 minutes and stirred sufficiently.
(2) One drop of the sample is caused to fall on the central part of a horizontally held filter paper (a filter paper for chromatography) by using a glass rod (having a diameter of 4 to 6 mm and a length of 150 to 200 mm and having the top end rounded by annealing).
(3) The sample-dropped filter paper is kept in the horizontal state and placed in a air bath tank maintained at a temperature of 100.degree..+-.2.degree. C., and is dried for 1 hour.
(4) The filter paper is taken out from the air bath tank, and the spot of the sample spread on the filter paper is compared with reference spots with respect to the form and characteristics and stability of a reference spot conformable to the sample spot is selected.
No particular problem arises when the stability of heavy oil is evaluated in a chemical laboratory according to this method, but if this test method is carried out on a vessel having no experimental equipment, various experimental tools and devices become necessary and the test cannot be performed simply.